Internal combustion engines



June 23, 1964 A. cAUvlN INTERNAL coMBusTIoN ENGINES Filed May 25, .1962.

United States Patent O 3,138,148 INTERNAL CMBUSTIN ENGINES Andr Cauvin, Port-Marly, France, assigner to Simca Automobiles, Paris, France, a company of France Filed May 23, 1962, Ser. No. 197,121 Claims priority, application France Ang. 12, 1961 Ciairns. (Cl. 12S-119) The present invention relates generally to internal combustion engines, and more particularly is directed to improvements in the breather pipe systems of such engines by which the crankcase is vented to the intake manifold or carburetor.

It is known that, in an internal combustion engine, a certain proportion of the gases compressed in the combustion chambers escapes during the power stroke by passing between the piston rings, and the cylinder walls. This phenomenon is generally known as blow by or gas passage. While relatively insignificant in new engines, this gas passage increases with the wear of the engine which results in ovalisation of the cylinders and wear of the piston rings. A certain part of the combustion gases thus enters the lower casing or crankcase of the engine, and is evacuated therefrom by a breather pipe extending to the intake manifold or carburetor of the engine.

With the breather pipes at present in use, the suction created in the engine crankcase by way of the breather pipe may become so great that external air enters the crankcase through the sealing gaskets of the engine, possibly along with impurities.

In order to avoid the above disadvantageous possibility in accordance with the present invention, the communication between the enclosed space of the crankcase and the intake manifold or carburetor by way of the breather pipe has a valve interposed therein which reduces or even eliminates the communication between this enclosed space and the breather pipe, when the suction prevailing in the crankcase reaches a predetermined value.

There are described hereinafter, by way of non-limitative examples, Various embodiments of the invention, with reference to 'the accompanying drawings wherein:

FIGURE 1 is a sectional view of a first embodiment of the invention.

FIGURE 2 is a sectional view of a second embodiment of the invention.

FIGURE 3 is a sectional view of a third embodiment of the invention.

FIGURE 4 is a diagrammatic side elevational View of an internal combustion engine provided with a breather system in accordance with this invention.

In the embodiment represented in FIGURE l, the suction-limiting valve provided according to the invention is made integral with the oil-filter cap, which is generally identified by the reference numeral 1. This cap is fixed in detachable fashion on an enclosed space 2 which communicates with the crankcase and, in the illustrated example of FIGURE 4, is the cylinder head cover, within which there prevails the same pressure as in the lower casing or crankcase C of the engine E, the communication between the enclosed space 2 and the casing of the engine being effected through a suitable pipe P or other known means. The securing of the cap 1 on the enclosed space 2 is effected by a known device which generally comprises a spring retainer 3, and a dome 4 supporting a bar 5, and will not be here described in greater detail.

On the upper part of the cap 1 there is fitted a sealed lid 6 in which there is provided a hole 7 establishing communication between the atmosphere and the outer face of an elastic diaphragm 8, for example of rubber. The upper or outer face of this diaphragm 8 is thus subjected to atmospheric pressure while its lower or internal face is subjected to the pressure prevailing in the enclosed space 3,138,148 Patented .lune 23, 1964 2 (and consequently in the engine casing) through a channel 23 extending between the enclosed space 2 and a cavity 1a provided in the cap 1 beneath the diaphragm. To the center of the diaphragm 8 there is fixed a conical valve needle 9 directed towards the interior of the cap and the cone of which is situated opposite a seating 10 of corresponding shape provided at the upper end of a blind bore 11, situated in the axis of the cap 1. A spring 12 is mounted in the bore 11 between the valve needle 9 and the bottom of the bore to push the needle 10 to a position where a certain clearance exists between the surfaces of the valve needle and the seating 10. Furthermore a channel 13 extends from the bore 11 and opens into a flexible pipe 14 which extends to the intake system of the engine, for example, as shown on FIGURE 4, to the carburetor I at a location on the latter between its throttle valve and fuel jets.

It will be noted that with the device according to the invention the enclosed space of the engine, which is completely sealed, cannot communicate with the exterior through any part of the cap 1 or of the attached parts. The position of the diaphragm 8 is thus a function of the difference between the atmospheric pressure and that prevailing in the enclosed space 2, and the same is the case with the position of the needle 9, which is secured to the diaphragm.

The operation of the apparatus is therefore as follows:

Since the enclosed space 2 of the engine is sealed, a suction is created therein by way of the channel 23, the space 1a, the clearance between the needle 9 and its seating 10, the blind bore 11, the channel 13 and the flexible pipe 14, s0 that the vapours present in the sealed enclosed space of the engine are thus conveyed into the engine through the carburetor. However, if in the course of operation the decreased pressure produced by this suction in the enclosed space 2, drops below a specific value, the atmospheric pressure exerted upon the diaphragm 8 will cause bending or flexing of the latter, thus bringing the needle 9 closer to its seating 10 and reducing the clearance between these two elements and conseqeuntly tending to diminish the pressure drop in the enclosed space 2. In the extreme condition where the suction exerted by the pipe 14 is truly too great, the needle 9 is applied upon its seating 10, temporarily cutting off all communication between the enclosed space 2 and the suction pipe 14. When the reduction of pressure in the enclosed space 2 has been lessened, the spring 12 forces the needle 9 into the open position.

In the above-described device, the cap 1 further fulfills its normal function of being removable to permit the filling of the casing of the engine with oil, the flexible pipe 14 remaining fixed to the said cap when the latter is separated from the engine.

FIGURE 2 shows another embodiment of the invention in which a valve actuator 9a fixed to the diaphragm, 8a acts upon a slide valve 15 having an axial blind bore 18 with radial ports 16 opening therefrom into an external i circular groove 17, which is adapted to register more or less with the channel 13 and therefore is capable of communicating between the latter and the enclosed space 2 through ythe port 16 and blind bore 18. The slide valve 15 is urged to its illustrated open position by a spring 19. It will be apparent that, when the pressure drop prevailing in the enclosed space 2 is too great, the valve actuator 9a pushes the slide valve 15 downwardly, tending to interrupt the communication effected through the ports 16 between the channel 13 and the enclosed space of the engine. Thus the operational conditions described with reference to the first embodiment of the invention are again achieved.

FIGURE 3 represents a further embodiment of the invention, wherein the diaphragm has been omitted. The external or atmospheric air acts directly upon the outer face 2G of a wide slide valve 15a, arranged substantially like the slide valve l5 of the embodiment of FIGURE 2. The upper surface 20 of this slide valve is sufficiently great so that the ditterence between the atmospheric pressure acting upon it, on the one hand, and the pressure prevailing in the enclosed space of the engine and acting upon the inner face 21 of the slide valve 35a, on the other hand produces a suii'icient force to effect downward movement of this slide valve against an opposing spring 22. It is apparent that the general conditions of operation are the same as in the previously described ernbodiments.

It is of course possible to form the valve according to the invention as a device independent of the cap 1 and communicating at another point with the enclosed space of the engine. In order to achieve satisfactory operation, it is necessary that the oil ller cap be sealed, as well as the entire casing of the engine.

Naturally the invention is not limited to the precise embodiments thereof described above with reference to the accompanying drawing, and various changes and modiiications may be made therein by one skilled in the art without departing from the scope and spirit of the invention which is intended to be defined by the appended claims.

What I claim is:

1. An internal combustion engine having an oil iller cap defining an enclosed space in communication with the crankcase of the engine, a breather pipe extending from said oil filler cap for connecting the crankcase of the engine with the intake system of the latter, and a valve located in said ller cap to regulate the communication between said enclosed space and the breather pipe and being subject to the action of the reduced pressure prevailing in the crankcase.

2. An internal combustion engine having a breather pipe for connecting the crankcase of the engine with the intake system of the latter, a valve located on an enclosed space in communication with the crankcase at the point from which said breather pipe extends, said valve serving to regulate the communication between said enclosed space and the breather pipe, a flexible diaphragm exposed, at one side, to the pressure in said enclosed space and, at its other side, to atmospheric pressure so as to be moved by the latter upon the occurrence of reduced pressure in the crankcase, means for transmitting the movement of said diaphragm to said valve, and spring means acting on said valve to oppose movement of the latter by said diaphragm and tending to move said valve to an open position of the latter.

3. An engine as in claim 2; wherein said valve is tixedly attached to said diaphragm.

4. An engine as in claim 2; wherein said diaphragm is separate from said valve and carries an actuating member bearing against said valve to constitute said means for transmitting the movement of the diaphragm to the valve.

5. An internal combustion engine having a breather pipe for connecting the crankcase of the engine with the intake system ot the latter, a valve located on an enclosed space in communication with the crankcase at the point from which said breather pipe extends, said valve serving to regulate the communication between said enclosed space and the breather pipe, said valve being in the form of a slide valve having relatively large, oppositely facing surfaces exposed to the pressure in said enclosed space and to atmospheric pressure, respectively, so that the valve is subject to the action of the reduced pressure prevailing in the crankcase.

References Cited in the file of this patent UNITED STATES PATENTS 2,240,459 McDowell Apr. 29, 1941 2,450,864 Callaway et al, Oct. 5, 1948 2,742,057 Krieck Apr. 17, 1956 

1. AN INTERNAL COMBUSTION ENGINE HAVING AN OIL FILLER CAP DEFINING AN ENCLOSED SPACE IN COMMUNICATION WITH THE CRANKCASE OF THE ENGINE, A BREATHER PIPE EXTENDING FROM SAID OIL FILLER CAP FOR CONNECTING THE CRANKCASE OF THE ENGINE WITH THE INTAKE SYSTEM OF THE LATTER, AND A VALVE LOCATED IN SAID FILLER CAP TO REGULATE THE COMMUNICATION BETWEEN SAID ENCLOSED SPACE AND THE BREATHER PIPE AND BEING SUBJECT TO THE ACTION OF THE REDUCED PRESSURE PREVAILING IN THE CRANKCASE. 